An electric vehicle or a plug-in hybrid electric vehicle is equipped with an inverter and a low voltage battery. The inverter is used to drive a motor with a high voltage battery for power-driving, and the low voltage battery is used to actuate auxiliary machines such as a vehicle light and a radio. This type of vehicle is equipped with a DC/DC converter which converts the power from the high voltage battery to the low voltage battery, or from the low voltage battery to the high voltage battery (see PTL 1, for example).
In such a vehicle, it is desired to improve the inhabitability by maximizing the proportion of interior room space to an entire vehicle volume. Therefore, it is desired that the inverter and the DC/DC converter be mounted in a minimum space outside the vehicle room, especially in an engine room.